Unless woefully short on greens I only eat leaves in good fresh condition. I don't mind holes from insects, but I can't see any reason to eat yellowed or withered stuff.

Well, I would only use those just beginning to show signs that it will yellow.

I wouldn't bother. They will not taste good. Pull off any yellowing leaves and put them on the compost. Eat the fresh green stuff. That's why you grow your own. If you want yellowing stale vegetables you can get them from a shop.

Point taken. I just thought "why waste?". I'll compost it.

The yellowing leaves won't hurt you or lead you to a vitamin deficiency, so there is no harm in trying them and seeing what you think. Since they are withering, they probably are less nutritious than the healthier leaves but not devoid of nutrition. Carbohydrates and sugars are probably a bit depleted, some vitamin content may be lower.

That said, I just toss yellowed leaves and eat the best--after all, if I'm growing them, I get first pick on eating the most desirable, the sheep can get the rest later.